Re: How to add a display property when a char appear in a buffer.

[Feng Shu]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: "Feng Shu" <tumashu@163.com>
>> Date: Mon, 29 Nov 2021 11:20:34 +0800
>> 
>> I want to auto add display property :min-width '(2.0), when a char
>> *appear* into a buffer. this char maybe inserted by user command, maybe
>> inserted in elisp.
>
> If it's inserted by a user command, you can write a slightly different
> command that puts the property.  If you want to cover also insertions
> from Lisp, I think the only good mechanism is to register a jit-lock
> function.
>
> But IMNSHO, it is not a good idea to put this property on individual
> characters, not at all.  You will end up with buffers that have many
> display properties, and that slows down redisplay, makes the Emacs
> memory larger, etc.  Don't do that!
>
> The right way of making double-width character occupy exactly 2
> columns on GUI frames is to tweak their pixel_width on the level of
> the display code, under the control of some variable, similar to what
> I did with height (which you didn't like, but here we are talking
> about width, not height)).  We are discussing such a feature on this

wow, good news :-)


> list, so I suggest that you follow that discussion and provide input
> and feedback where you see fit.

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